1. Field of the Invention
The invention is directed to a toolholder for cutting inserts used for metalworking operations and, more specifically, a blade which secures a cutting insert and is removably attached to the toolholder.
2. Description of the Related Art
During a metalworking operation in which a cutting insert is used to produce a slot for grooving or for cutting off a workpiece, the thickness of the slot imparted by the cutting insert dictates the thickness of the toolholder supporting the cutting insert. As an example, if a cutting insert must penetrate a workpiece to a depth of two inches in order to perform a cutting operation, then at least two inches of the toolholder must also extend within the slot created by the machining operation. It is not unusual to create a groove having a thickness of less than one-sixteenth inch and, as a result, the associated portion of the toolholder must be slightly less than one-sixteenth inch to clear the machined slot. Because of this low thickness, the toolholder may be relatively fragile and any unexpected forces upon the toolholder may be sufficient to damage the toolholder.
When a portion of the toolholder supporting the cutting insert is an integral part of the toolholder, and when the toolholder is damaged and must be replaced, the entire toolholder must be replaced. This is expensive and inconvenient even when the toolholder is a relatively simple and conventional square shank toolholder. However, it is especially expensive and inconvenient when the toolholder is of a type designed for quick change applications. Under these circumstances, the end of the toolholder opposite the cutting insert may be intricately machined so that it may be relatively easily mounted and dismounted within the spindle of a machine tool. For that reason, replacement of such a toolholder can be very expensive.
U.S. Pat. No. 4,898,054 to Bystrom et al. discloses an arrangement utilizing a planar elongated blade with top and bottom angled surfaces which engage matching surfaces on the toolholder. The arrangement also utilizes a wedge to clamp a protruding portion of the blade against the toolholder. Not only is the design of the blade relatively complex but the trailing portion of the wedge 12 is not laterally supported at the end of the blade opposite the cutting insert.
U.S. Pat. No. 5,688,080 to Hedlund is directed to a removable blade utilizing bolts extending through the side of a blade to secure the blade within a toolholder. The blade has a cavity which mates with a projection from the toolholder to provide additional lateral support from the blade. However, just as before, this arrangement provides little lateral support to the blade.
A design is therefore sought for a detachable blade on a toolholder whereby the detachable blade is amply supported in both lateral and vertical directions to resist forces imposed upon the blade during a machining operation.